Measurement of the Multi‐TeV Gamma‐Ray Flare Spectra of Markarian 421 and Markarian 501

The energy spectrum of Markarian~421 in flaring states has been measured from0.3 to 10 TeV using both small zenith angle and large zenith angle observationswith the Whipple Observatory 10 m imaging telescope. The large zenith angletechnique is useful for extending spectra to high energies, and the extractionof spectra with this technique is discussed. The resulting spectrum ofMarkarian~421 is fit reasonably well by a simple power-law. This is in contrastto our recently reported spectrum of Markarian 501 which, over a similar energyrange, has substantial curvature. The differences in TeV energy spectra ofgamma-ray blazars reflect both the physics of the gamma-ray productionmechanism and possibly differential absorption effects at the source or in theintergalactic medium. Since Markarian~421 and Markarian~501 have almost thesame redshift (0.031 and 0.033 respectively), the difference in their energyspectra must be intrinsic to the sources and not due to intergalacticabsorption, assuming the intergalactic infrared background is uniform.Comment: 24 pages, 7 figures, accepted for Publication in Ap